domains
	sentence	= sentence(noun_phrase, verb_phrase)
	noun_phrase	= noun(noun); noun_phrase(determiner, noun_expression)
	noun_expression	= noun(noun); noun_expression(adjective, noun)
	noun		= string
	adjective	= string
	
	verb_phrase	= verb(verb); verb_phrase(verb, noun_phrase)
	verb		= string
	determiner	= string

predicates
	s_sentence(string, sentence) - nondeterm (i,o)
	s_noun_phrase(string, string, noun_phrase) - nondeterm (i,o,o), nondeterm (i,i,o)
	s_verb_phrase(string, verb_phrase) - nondeterm (i,o)
	s_noun_expression(string, string, noun_expression) - nondeterm (i,o,o), nondeterm (i,i,o)
	
	nondeterm command_loop
	nondeterm write_message
	
facts - general
	a(string) %- determ (i)
	d(string) %- determ (i)
	n(string) %- nondeterm (i)
	v(string) %- determ (i)
		
clauses
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	%%%%%% 一個句子可拆分為名詞短語和動詞短語 %%%%%%%
	s_sentence(Str, sentence(N_Phrase, V_Phrase)):-
		s_noun_phrase(Str, Rest, N_Phrase),
		s_verb_phrase(Rest, V_Phrase).
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	%%%%%%%%%%%%%% 分析名詞短語  %%%%%%%%%%%%%%%%%%%%%		
	s_noun_phrase(Str, Rest, noun_phrase(Deter, N_Exp)):-
		fronttoken(Str, Deter, Rest1),
		d(Deter),
		write("article=", Deter), nl,
		s_noun_expression(Rest1, Rest, N_Exp).		
		
	/*s_noun_phrase(Str, Rest, noun(Noun)):-
		fronttoken(Str, Noun, Rest),
		not(n(Noun)),write("This program doesn't know the word:", Noun), nl,
		write("Please append it to the database!"), nl,
		command_loop.	*/

	s_noun_phrase(Str, Rest, noun(Noun)):-
		fronttoken(Str, Noun, Rest),
		n(Noun),
		write("noun=", Noun), nl.	
			
	s_noun_expression(Str, Rest, noun_expression(Adj, Noun)):-
		fronttoken(Str, Adj, Rest1),
		a(Adj),
		fronttoken(Rest1,Noun,Rest),
		n(Noun),
		write("adjective=", Adj), nl,
		write("noun=", Noun), nl.		
		
	s_noun_expression(Str, Rest, noun(Noun)):-
		fronttoken(Str, Noun, Rest),
		n(Noun),
		write("noun=", Noun), nl.	
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%	
	%%%%%%%%%%%%% 分析動詞短語 %%%%%%%%%%%%%%%%%%		
	s_verb_phrase(Str, verb(Verb)):-
		fronttoken(STR, Verb, ""),
		v(Verb),
		write("verb=", Verb), nl.
		
	s_verb_phrase(Str, verb_phrase(Verb, N_Phrase)):-
		fronttoken(Str, Verb, Rest1),
		v(Verb),
		write("verb=", Verb), nl,
		s_noun_phrase(Rest1, "", N_Phrase).		
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%	
	%%%%%%%%%%%%%%%% 單詞數(shù)據(jù)庫 %%%%%%%%%%%%%%%%%%
	/* adjective */
	a("big").
	a("small").
	a("brown").
	a("lazy").
	
	/* article */
	d("the").
	d("a").
	
	/* noun */
	n("dog").
	n("bone").
	n("mouse").
	n("cat").

	/* verb */
	v("ate").
	v("eat").
	v("chases").
	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
	%%%%%%%%%% 循環(huán)提示輸入句子并分析 %%%%%%%%%%%%
	command_loop:-
		write("Please input a sentence:"),
		nl,
		readln(S),
  		not(s_sentence(S, _)),
  		write_message,
  		command_loop.
  		
  	command_loop:-
		write("This is a valid sentence!"), nl, nl,
		command_loop.
  	
  	write_message:-
  		write("This is a invalid sentence!"), nl, nl.
	
goal
	command_loop.